Fluence and pressure effects on IR multiphoton dissociation of ethylbromide

✍ Scribed by Jang Soo Shin; Chang Ju Choi; Kyung-Hoon Jung; Cheol Jung Kim

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 716 KB
• Volume: 84
• Category: Article
• ISSN: 1010-6030
• DOI: 10.1016/1010-6030(94)03862-7

✦ Synopsis

The IR multiphoton dissociation of C,H,Br was studied as a function of the laser fluence and substrate pressure using a pulsed TEA CO, laser at the lOP(20) (10.59 pm, 944 cm-') laser line. The effects of added H,, He, Na and NO were also studied. The reaction products were found to be GH,, GH,, GH, and CHA. The increase in the partial pressure of the products with increasing substrate pressure was interpreted in terms of the large contribution from a collision-induced reaction between the reactant molecules excited below the reaction threshold. At a focal fluence of less than 100 J cm-*, GH, was the only reaction product detected, whereas CH, and CHa also appeared at higher fluence. The formation of GH, and CH, at higher fluence was attributed to additional laser photon absorption by vibrationally excited ethylene (CaH,*) p &arily in the quasi-continuum state. The production of C& was due to C-Br bond fission. The observed dissociation data were compared with the theoretical predictions obtained using the energy-grained master equation.